1. Field of the Invention
The invention relates to the opening of thin packaging, typically made of plastic material.
2. Description of the Related Art
In a conventional manner, various consumer products (packets of biscuits, cigarettes, CDs, DVDs, etc.) are covered with packaging formed by a thin film (or sheet) which is weak, i.e. capable of being torn. Such packaging allows effective protection of the product during the period of time between the end of the manufacture of this product and its entry into service; this means that, before the product is put into service, this packaging must be removed. When such removal is carried out manually, i.e. without a tool, it is achieved in practice by random tears until it is possible to remove the portions of packaging thus separated.
It is well known that such random tears do not allow reliable and rapid removal of the packaging. In fact, with the fingers it is rare to manage to cause a tear which propagates correctly to the extent that it separates two packaging parts which are easy to remove; on the contrary, it is often necessary to make several tears each of which tends to break off rapidly; the number of successive tears that have to be caused is particularly large when it is necessary to start a tear oneself from an edge of the packaging film.
In order to remedy this situation, it has already been proposed to form an incipient tear in the packaging film, typically in the form of a precut tab. But it became apparent that, when a fragile film is torn by pulling on such a precut tab, the sides of the latter tend to converge towards each other during tearing, which results in the detachment of a simple tapered flap, so that a new incipient tear must be sought, which results in the tearing off of a new flap, and so on.
It has also been proposed to combine with a precut tab a strip of underlying material intended to guide the tear in an appropriate manner; however, unless this strip is secured to the packaging film over its entire length (which proves to be complex in practice and risks weakening the packaging inasmuch as it serves as protection thereof), it is not unusual for this strip to allow guiding only as far as the end of the tear line provided. And, assuming that this strip allows guiding of the tear all along this strip, there may then be difficulties in removing the product from the container formed by the remainder of the packaging, given the friction between this product and the inner wall of this packaging (it may be necessary to produce an additional tear line, with the abovementioned difficulties).
To date there is therefore no packaging film making it possible, without complex preparation of the latter, to ensure easy opening of this film in so as to allow removal in a very small number of pieces.